There are many applications where the exterior of a product is required to have design properties. Such products include cellular phones, housings of personal computers, electrical appliances, furniture and automobiles. There is also an increasing demand for design properties. For the purpose of imparting design properties, methods of pasting a colored film or transferring a printed film surface onto a substrate are known. In addition, multi-layer laminated films that comprise two kinds of resins alternately laminated in the thickness direction and show coloration and reflection of light by utilizing the interference reflection phenomenon exhibited by the resins have been recently made known as a means of imparting design properties. For example, multi-layer laminated films that utilize interference reflection to show metallic luster (Japanese Translated PCT Patent Application Laid-open No. 2003-511729 and Japanese Patent Application Laid-Open Publication (JP-A) No. 2007-268709), a multi-layer laminated film having a near-infrared reflecting function (Japanese Patent No. 4534637) and a multi-layer laminated film having a scattering preventive function (Japanese Patent Application Laid-Open Publication (JP-A) No. H10-076620) are known. Those molded articles produced by hot-press lamination of these multi-layer laminated films on a hard support and subsequent molding of the resulting laminates are used as decorative materials such as decoration panels as well as in various household electric appliances, building articles, automobile-related parts and the like.
In recent years, in response to the introduction of carbon dioxide emission controls for environmental protection, heat ray-shielding glasses capable of suppressing the inflow of heat from outside, particularly sunlight, during summertime have been drawing attention as window glasses of vehicles such as cars and trains and those of buildings.
Examples of such heat ray-shielding glasses include those in which a heat ray-absorbing material incorporated into a glass or an interlayer constituting a laminated glass is used to reflect heat rays (for example, Japanese Patent Application Laid-Open Publication (JP-A) No. 2010-17854); those in which a metal coating layer formed on a glass surface by sputtering or the like is used to reflect and block heat rays (for example, Japanese Patent No. 3901911); and those in which a polymer multi-layer laminated film produced by alternately laminating polymers having different refractive indices is inserted between glasses and interlayers and used to reflect and block heat rays (for example, Japanese Patent No. 4310312). Thereamong, however, in a method of using a heat ray-absorbing material, since the heat ray-absorbing material converts sunlight entering from outside into thermal energy, there is a problem that the thus generated heat radiates into the room and the heat ray-shielding efficiency is consequently reduced. In addition, absorption of heat rays partially increases the glass temperature and the resulting difference between the glass temperature and the ambient temperature may damage the glass itself. Moreover, in a method of forming a metal coating layer on a glass surface by sputtering or the like, since the metal coating layer reflects not only heat rays but also visible light, it is likely to cause coloration. Furthermore, since the metal coating layer blocks electromagnetic waves as well, it may impede the use of communication devices and the like inside.
Meanwhile, in a polymer multi-layer laminated film, the wavelengths to be reflected can be selected by controlling the layer thickness. Therefore, the film can be made to selectively reflect light in the near-infrared range so that the heat ray-shielding performance of a glass can be improved while maintaining the visible light transmittance. In addition, since such a polymer multi-layer laminated film does not contain any radio wave-blocking material such as metal, it can retain excellent radio wave permeability.
Molded articles of those multi-layer laminated films are used in places exposed to the public eye. Therefore, the outer appearance is important. Yet, since such molded articles experience, for example, delamination of printing resistant layer or damage caused by scratching with a sharp object, there is an increasing demand for durability and resistance against damage. The same demand has been made also in the above-described example of pasting a film. However, as a problem unique to films, there is a problem that, for example, irregular pressing due to irregularities in thickness of an interlayer laminated with a support and a difference between the heat shrinkage stress between the film and interlayer cause irregular strains to be generated in the film during molding and this consequently deteriorates the outer appearance. Particularly, in multi-layer laminated films, it has been pointed out that such irregularities are likely to stand out as an optical defect since multi-layer laminated films utilize the interference reflection phenomenon provided by controlling the layer thicknesses. When a support(s), an interlayer(s) and a multi-layer laminated film are laminated and molded, as other problem, generation of wrinkles is also problematic. This primarily occurs in the edge portions of the resulting molded article due to, for example, the inability of the multi-layer laminated film to conform to the shape of the support during the molding or the difference in the heat shrinkage rate between the film and the interlayer. Meanwhile, generation of irregular strains, which is a problem, is different from generation of wrinkles in that it occurs over the entire surface of the resulting molded article regardless of the shape of the support and that it is attributed to irregular pressing caused by thickness variation of the interlayer or a difference between the heat shrinkage stress between the interlayer.
It could therefore be helpful to provide a multi-layer laminated film which inhibits the generation of irregular strains caused by hot-press molding in a molded article comprising the multi-layer laminated film, and an interlayer and a support that are arranged on at least one side of the multi-layer laminated film; and to thereby obtaining a molded article having excellent outer appearance and design.